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<head><meta charset="utf-8"><title>Stabilizing  the ARM SIMD types? · t-libs/stdarch · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/index.html">t-libs/stdarch</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html">Stabilizing  the ARM SIMD types?</a></h3>

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<a name="205657681"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205657681" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205657681">(Aug 01 2020 at 01:34)</a>:</h4>
<p>While I understand that we have a long way to go before stabilizing all the ARM intrinsics themselves, would it be possible to stabilize just the SIMD types for ARM?</p>



<a name="205679605"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205679605" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Amanieu <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205679605">(Aug 01 2020 at 12:35)</a>:</h4>
<p>What do you need them for?</p>



<a name="205681279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205681279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205681279">(Aug 01 2020 at 13:24)</a>:</h4>
<p>Well, a person could just link with the correct LLVM intrinsics themselves in the mean time if the types (and thus the simd abi on the functions using the types) were available.</p>
<p>And I don't think that the types themselves are going to change as <code>stdarch</code> develops further. It's pretty obvious what <code>float32x4_t</code> <em>is</em> as a type.</p>



<a name="205687489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205687489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Amanieu <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205687489">(Aug 01 2020 at 16:12)</a>:</h4>
<p>Linking to LLVM intrinsics is still unstable though so stabilizing the types won't help in that case.</p>



<a name="205690612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205690612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205690612">(Aug 01 2020 at 17:30)</a>:</h4>
<p>That's a little puzzling, because within stdarch, the external intrinsics that perform the various llvm functions are all declared as extern C. Does the compiler have some special check on the link name given to prevent a link if the name starts with "llvm.", or something like that?</p>



<a name="205690709"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205690709" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205690709">(Aug 01 2020 at 17:32)</a>:</h4>
<p>Specifically what I would like to do is continue to develop the <code>wide</code> crate, but the "point" of that crate over <code>packed_simd</code> is that it works on Stable instead of Nightly.</p>



<a name="205690861"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205690861" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Amanieu <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205690861">(Aug 01 2020 at 17:37)</a>:</h4>
<p>Yes rustc specifically rejects symbol names starting with "llvm.": <a href="https://github.com/rust-lang/rust/blob/cfdf9d335501cc0a53ae69c940095cca7d4be0f8/src/librustc_ast_passes/feature_gate.rs#L396">https://github.com/rust-lang/rust/blob/cfdf9d335501cc0a53ae69c940095cca7d4be0f8/src/librustc_ast_passes/feature_gate.rs#L396</a></p>



<a name="205691471"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/208962-t-libs/stdarch/topic/Stabilizing%20%20the%20ARM%20SIMD%20types%3F/near/205691471" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/208962-t-libs/stdarch/topic/Stabilizing.20.20the.20ARM.20SIMD.20types.3F.html#205691471">(Aug 01 2020 at 17:52)</a>:</h4>
<p>I've never sighed harder in my life.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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